Sofa bed and linkage mechanism

ABSTRACT

A sofa bed including a base, a seat section; and a back-rest section movable relative to the seat section between a generally upright position when the sofa bed is positioned for use as a sofa bed and a retracted, generally horizontal position coplanar with the front section when the sofa bed is positioned for use as a bed. In the sofa position, the seat section rests on the base with the back-rest section projecting generally upwardly at the rear side of the seat section while in the bed position, the seat section is displaced upwardly and forwardly relative to the base while the back-rest section is displaced forwardly into a horizontal portion coplanar with the seat section and overlying the base. The seat and back-rest sections are supported relative to the base by linkage mechanism which includes on each end thereof, front and rear swing arms both of which are pivotally mounted to the base at their lower ends with the front swing arm being pivotally connected at its upper end to the seat section. The upper end of the rear swing arm is pivotally connected to a carrier link, one end of which is pivotally connected to the back-rest section with an intermediate portion thereof being pivoted to an intermediate portion of the front swing arm. The forward extremity of the carrier link is pivotally connected to an actuating link which in turn is pivotally connected to a support leg for the seat section to move the support leg between extended and retracted positions when the sofa bed is moved between the bed and sofa positions.

United States Patent Rogers, Jr. et al.

[54] SOFA BED AND LINKAGE MECHANISM [72] Inventors: Walter Clark Rogers, Jr., 1207 Hurdover Street, High Point, NC. 27262; Morton Snitzer, 3217 Ridgecrest Drive, Rocky Mount, NC. 27801 22 Filed: Dec.7, 1970 21 Appl.No.: 95,695

[52] U.S. Cl. ..5/29, 5/37 [51] lnt.Cl... [58] Field of Search Katz ..5/13

Primary Examiner-Casmir A. Nunberg Attorney-Beveridge & De Grandi [5 7 1 ABSTRACT A sofa bed including a base, a seat section; and a back-rest section movable relative to the seat section between a generally upright position when the sofa bed is positioned for use as a sofa bed and a retracted, generally horizontal position coplanar with the front section when the sofa bed is positioned for use as a bed. in the sofa position, the seat section rests on the base with the back-rest section projecting generally upwardly at the rear side of the seat section while in the bed position, the seat section is displaced upwardly and forwardly relative to the base while the back-rest section is displaced for wardly into a horizontal portion coplanar with the seat section and overlying the base. The seat and back-rest sections are supported relative to the base by linkage mechanism which includes on each end thereof, front and rear swing arms both of which are pivotally mounted to the base at their lower ends with the front swing arm being pivotally connected at its upper end to the seat section. The upper end of the rear swing arm is pivotally connected to a carrier link, one end of which is pivotally connected to the back-rest section with an intermediate portion thereof being pivoted to an intermediate portion of the front swing arm. The forward extremity of the carrier link is pivotally connected to an actuating link which in turn is pivotally connected to a support leg for the seat section to move the support leg between extended and retracted positions when the sofa bed is moved between the bed and sofa positions.

22 Claims, 5 Drawing Figures United States Patent [151 3,657,747 Rogers, Jr. et al. 1 Apr. 25, 1972 PATENTEI] APR 2 5 I972 v SHEET 1 [IF 3 PATENTED APR 2 5 I972 SHEET 2 BF 3 SOFA BED AND LINKAGE MECHANISM SUMMARY OF INVENTION AND OBJECTS The present invention relates to a novel sofa bed of the type which may be converted from a position wherein it is used as a sofa hereinafter termed sofa position" to a position wherein it is used as a bed hereinafter termed bed position. Additionally, the present invention relates .to novel linkage mechanism which although it is particularly suitable for use in a sofa bed, may have equal applicability elsewhere such as in a foldable seat.

One of the objects of the present invention is to provide a novel sofa bed which may be easily and quickly converted between the sofa and bed positions without requiring any skill or excessive manual effort.

A further object of the present invention is to provide such a sofa bed which may be relatively economically manufactured with a compact and attractive design without sacrificing ease of operability. Included herein is a provision of such a sofa bed which will be comfortable to the user while moreover being susceptible to manufacture in various designs with or without arm rests.

A further object of the present invention is to provide such a sofa bed which may be fabricated with a durable construction that will provide dependable service notwithstanding repeated use over long periods of time.

A still further object of the present invention is to provide a sofa bed which may be placed close to a wall in a room and operated from the same position without requiring initial movement of the sofa bed away from the wall to accommodate the bed position.

The above and other objects are achieved by a sofa bed embodying the invention including a base, a seat frame, and a back-rest pivotally connected to the rear of the seat frame for movement between a normal upright position when the sofa bed is in the sofa position and a horizontal position coplanar with the seat frame when the sofa bed is in the bed position. The seat and back-rest frames are supported on the base by a linkage mechanism such that in the sofa position, the seat frame rests on the base in generally overlying relationship with the back-rest frame projecting upwardly from the rear side of the seat frame generally over the rear side of the base. In moving to the bed position, the seat frame is raised and moved forwardly relative to the base while the back-rest frame swings downwardly towards the base relative to the seat frame while also moving forwardly relative to the base. In the bed position, the seat and back-rest frames are in coplanar side-by-side position with the back-rest frame overlying a substantial portion of the base and with the seat frame projected substantially forwardly of the base. When in the bed position the seat and back-rest frames are elevated from the base.

Any suitable mattress or cushion arrangement may be employed on the seat and back-rest frames. In one embodiment, one or more removable cushions may be employed on the back-rest frame when in the sofa position so that when converted into the bed position, these cushions may be removed. In this embodiment, the seat frame may contain a double layer mattress including upper and lower sections hinged together such that the upper section overlies the lower sections to form the cushion for the seat frame when in the sofa position. Inthe bed position, the top mattress section may be swung over onto the back-rest frame such that the seat and back-rest frames are entirely covered by the mattress. It is obvious that any other suitable arrangement or construction of cushion or mattresses may be employed.

In one embodiment of the invention, the linkage mechanism for supporting the seat and back-rest frames on the base includes at each end thereof, front'and rear swing arms both pivotally connected to the base at their lower ends with the front swing arm being pivotally connected to a rear portion of the seat frame. The rear swing arm is pivotally connected at its upper end to an intermediate portion of a generally L-shaped carrier link, one end of which is pivoted to a lower portion of the back-rest frame while an intermediate forward portion thereof is pivoted to an intermediate portion of the front swing arm. The front end of the carrier link is pivoted to the lower end of an actuator link the front end of which is pivoted to a foldable support leg for the seat-frame when in the bed position. This support leg is pivoted with respect to a front portion of the seat'frame for movement between an extended position for supporting the seat frame in the bed position and a retracted position when the seat frame is in the sofa position.

Movement of the leg rest between the extended and the retracted positions is achieved by the actuator link which in turn is operated by the carrier link.

In the'preferred embodiment, a torque tube is interconnected between the front swing arms of the linkage mechanisms on the opposite ends of the sofa bed to ensure that the linkage mechanisms move together inunison. 'Addi-' tionally, an over center spring mechanism isprovided to assist in moving the sofa bed between the sofa and bed positions and further to bias the sofa bed in both positions.

Other objects and advantages will become apparent from the following more detailed description taken in conjunction with the attached drawings in which:

FIG. 1 is a perspective view of a sofa bed frame into which the present invention may be incorporated;

FIG. 2 is a side elevational view of a sofa bed embodying the present invention with the cushions thereof being shown in phantom lines;

FIG. 3 is a view similar to FIG. 2 but with the sofa bed situated in a position intermediate the sofa position and the bed position;

FIG. 4 is a view similar to FIG. 3 but with the sofa bed situated in the sofa position; and

FIG. 5 is a plan view of the linkage mechanism illustrated in FIG. 4 with portions of the frame shown in phantom lines.

DETAILED DESCRIPTION back-rest frame 16 pivotally connected to the seat frame, and

a linkage mechanism 18 for supporting the seat and back-rest frames on the base.

Base 12 may have any suitable construction such as for example shown in the drawings wherein it includes front and rear side members 20 and 22 interconnected at the'ir'erids by end members 23 to form a generally rectangular structure. Similarily, seat and back-rest frames 14 and 16 may also have a rectangular construction including side members 24 and 26 respectively and end members'28 and 30 respectively. The frames may be made from wood as in the shown embodiment or any other suitable material.

Any suitable cushion or mattress arrangement may be provided. The shown embodiment includes a double mattress or cushion consisting of upper and lower sections 32 and 34 hinged together at 36 along their adjacent sides while being supported on seat frame 14 in overlying relationship when in the sofa position as shown in FIG. 2. To complete the cushion arrangement in this position, one or more removable cushions 38 may be placed against the back-rest as shown in FIG. 2.

In use, when as desired to convert the sofa bed from the sofa position shown in FIG. 2 to the bed position shown in FIG. 4, the back-rest cushions 38 are removed and then the seat frame 14 is raised and moved forwardly which will also cause the back-rest frame 16 to pivot clockwise as shown in the drawings relative to the seat frame 14 into a horizontal position coplanar with the seat frame and displaced forwardly overlying a substantial portion of base 12 as shown in FIG. 4. Upper mattress section 32 may then be swung clockwise as shown in the drawings about the hinge 36 to cover back-rest frame 16 thereby completing the conversion for bed use.

It will be noted that during the foregoing conversion base 12 remains stationary in the same position while the seat frame 14 is elevated and moved forwardly to project substantially beyond the base while the back-rest frame 16 is swung into horizontal position and at the same time translated forwardly to overlie a substantial portion of the base. This not only provides a compact swinging movement but also pennits the sofa bed to be placed close to a wall in a room since movement of the seat and back-rest frames 14 and 16 during conversion into the bed position occurs only in the forward direction, which is away from the wall.

In the shown embodiment of the invention shown, linkage mechanism 18 for supporting the seat and back-rest frames on the base is provided on opposite ends of the sofa bed in identical fashion. The specific embodiment of linkage mechanism 18 shown includes on each end of the sofa bed, front and rear swing arms 40 and 42, the lower ends of which are pivotally .connected by pivots 44 and 46 to an intermediate cross member 23' of the base at positions substantially spaced along the latter. The latter connection in an actual commercial embodiment may be achieved by a mounting bar 48 fixed such as by screws 49 to the base frame so 'as to receive pivot pins 44 and 46. Front swing arm 40 is slightly cranked at its upper portion 50, the end of which is pivotally connected by pin 52 with respect to the rear end portion of seat frame 14. The latter may beachieved in a commercial embodiment by a seat mounting plate 54 secured to an intermediate seat frame member 28 such as by screws, to pivotally receive front swing arm 40.

Rear swing arm '42 is shaped as shown in the drawings with an upper crank portion 60 which terminates at a pivotal connection 62 to what will be termed a carrier link" 64 which has a generally L-shape. Rear swing arm 42 is pivoted to an intermediate portion of a crank portion 66 of carrier link 64. Crank portion 66 of carrier link 64 is in turn pivoted by pin 68 with respect to a lower portion of back-rest frame 16. The latter connection may be achieved in a commercial embodiment through a back-rest mounting plate 70 secured to intermediate cross member 30 of the back-rest frame such as by screws 71. Seat frame mounting plate 54 and back-rest mounting plate 70 extend a sufficient length toward each other to meet at a pivotal connection 76 through which the seat frame and back-rest frame are interconnected for swinging movement in a vertical plane relative to each other.

A forward portion of carrier link 64 is pivotally connected by pin 78 to an intermediate portion of front swing arm 40, the latter occuring in the shown embodiment at the point where crank portion 50 of the front swing arm merges with the main portion of the front swing arm. The forward extremity of carrier link 64 is pivotally connected by pin 79 to the rear end of an actuator link 80 which is employed to actuate a foldable support leg 82 for the seat frame when the latter is in the bed position.

In the specific embodiment shown, support leg 82 has a generally U-shape including a cross portion 84 which is engagable with the floor for supporting the seat frame in the bed position, and a pair of arms 86 projecting from the opposite ends of cross portion 84. The upper or free ends of support leg arms 84 are fixed to one arm of a crank 90 which in turn is pivoted intermediate its ends by pin 91 to a bracket 92 fixed to the forward portion of the seat frame. The other end of crank 90 is pivoted by pin 93 to the forward end of the actuator link 80 to be rotated thereby about pivotal 91 for purposes of moving support leg 82 between extended and retracted positions which it occupies when the sofa bed is in the bed and sofa positions respectively.

In the preferred embodiment, a torque bar 100 which may be in the form of a tube as shown is fixed between the linkage mechanisms on the opposite ends of the sofa bed. As in the specific embodiment shown, the torque bar 100 may be fixed between the bottom ends of front swing arms 40. This will assure that the linkage mechanisms on opposite ends of the sofa bed will move in unison.

Further in the preferred embodiment, a spring generally designated 110 is provided to bias the sofa bed in both of the sofa and bed positions and also to assist in moving it to either position. Spring 110 is a tension type coil spring one end of which is anchored to the base such as through a bracket 112 fixed to cross member 23' on the base frame while the other end of spring 1 10 is anchored such as through a bracket 114 to the seat frame at a point adjacent the pivotal connection 76 between the seat and back-rest framesIBracket 114 is secured to the seat frame side member 24.

In use, when in the sofa position, the linkage mechanism 18 will be collapsed and the seat frame 114 positioned on the base as shown in FIG. 2. In this latter position, it will be noted that the front and rear swing arms 40 and 42 will extend rearwardly at slight angles from their pivotal connections 44 and 46 to the base, and the crank portion 66 of carrier link 64 will extend generally vertically as shown in FIG. 2. When it is desired to move the sofa bed into the bed position shown in FIG. 4, back-rest cushions 38 are first removed, and then seat frame 14 is pulled forwardly causing swing arms 40 and 42to pivot in a counter-clockwise direction as viewed in the drawings about their pivotal connections 44 and 46 to the base. This will cause the seat frame to be raised and displaced forwardly relative to the base. In addition, this will cause the back-rest frame to be pulled forwardly by the seat frame. At the same time the back-rest frame will start to swing clockwise about pivot 76 under the influence of carrier link 64 which is moved forwardly by swing arms 40 and 42.

Continued pulling of the seat frame forwardly will cause it to rise until front swing arm 40 reaches a substantially vertical position as shown in FIG. 3 whereupon continued forward movement of the seat frame will cause it to lower towards the floor until support leg 82 which during the latter movement was unfolding, engages the floor.

Unfolding movement of support leg 82 from the retracted position shown in FIG. 2 is achieved through the actuator link which in turn is operated by carrier link 64. In this regard, actuator link 80 serves to pivot crank in the clockwise direction (as viewed in the drawings) about pivotal connection 91 as the swing arms are swung forwardly in the counterclockwise direction relative to the base during movement of the seat frame into the bed position. When the sofa bed is fully moved into the bed position, upper mattress'section 32 may then be pivoted about hinge 36 in the clockwise direction (as viewed in the drawings) until it overlies and engages back-rest frame 16.

Return of the sofa bed into the sofa position is accomplished by reversing the above steps.

What is claimed is:

l. A sofa bed including in combination, a base, a seat, a back-rest, means pivotally interconnecting the back-rest and the seat permitting the back-rest to move between an upright position and a generally horizontal position generally coplanar with the seat, and linkage means supporting said back-rest and said seat on said base for movement between a sofa position wherein said seat closely overlies said base with said back-rest in upright position, and a bed position wherein said back-rest and said seat are in generally coplanar relationship with the back-rest overlying a substantial portion of said base and with the seat projected forwardly from the base, said linkage means including a front swing arm pivotally connected to the base, a e

rear swing arm pivotally connected to said base rearwardly of said front swing arm, and a carrier link pivotally connected to said back-rest and said front swing arm, one of said carrier link and said front swing arm being connected to said seat.

2. A sofa bed or similar structure including in combination,

a base, a seat, a back-rest, means pivotally interconnecting said back-rest to said seat for movement between an upright position and ahorizontal position generally coplanar with the seat, linkage means for supporting said seat and back-rest 7 between a sofa position wherein said seat overlies said base in close relationship therewith, said back-rest extending in generally upright position and a bed position wherein said seat is projected forwardly from the base-with said back-rest in a horizontal position substantially coplanar with said seat, said linkage means including front and rear swing arms having lower end portions pivotally connected with respect to said base for swinging movement generallyin a vertical plane, said front swing arm having an upper portion pivotally connected with respect to said seat, a carrier link having one end portion pivotally connected with respect to the back-rest and an intermediate portion pivotally connected with respect to said front swing arm, said rear swing arm being pivotally connected with respect to an intermediate portion of said carrier link.

3. The structure defined in claim 2 further including a foldable support leg pivotally connected to said seat for movement between a retracted position under said seat and extended position projecting downwardly from said seat to support the same when in the bed position, means interconnecting said support leg and said linkage means for actuating said leg between the extended and retracted positions thereof in response to movement of said linkage means.

4. The structure defined in claim 3 wherein said last defined means includes an actuator link pivotally connected to said carrier link. 1

5. The structure defined in claim 4 further including a spring means for biasing the structure in said sofa and bed positions.

6. The structure defined in claim 5 wherein said spring means includes a tension spring having one end anchored with respect to said base and having an opposite end connected to said seat.

7. The structure defined in claim 4 wherein said carrier link has a generally L-shape including a main portion and a crank portion projecting from a rear end portion of the main portion, said rear swing arm being connected to said crank portion, said crank portion being the portion of said carrier link which is pivotally connected to said back-rest as defined above.

8. For use in a sofa bed or similar structure for supporting a seat and a back-rest on an underlying base for movement between a sofa position wherein the seat generally overlies the base with the back-rest in generally upright position and a bed position wherein the seat is projected forwardly from the base and the back-rest is in horizontal position generally coplanar with the seat; a linkage mechanism including a front swing arm and a rear swing arm, the lower ends of said front and rear swing arms adapted to be pivotally connected with respect to the base, the upper end of said front swing arm adapted to be pivotally connected to said seat, a carrier link having a rear portion adapted to be pivotally connected with respect to the back-rest and having a forward portion pivotally connected with respect to an intermediate portion of said front swing arm, said rear swing arm having a portion pivotally connected with respect to a rear portion of said carrier link.

9. The linkage mechanism defined in claim 8 further including a leg support for the seat adapted to be pivotally connected with respect to the seat for movement between retracted and extended position relative to the seat, and an actuator link having one end portion pivotally connected to said carrier link and an opposite end portion pivotally connected to said leg support to actuate the leg support between extended and retracted positions.

10. The linkage mechanism defined in claim 9 wherein said carrier link has a generally L-shape including a main portion and a crank portion projecting from a rear end portion of the main portion, said rear swing arm being connected to said crank portion, said crank portion being the portion of said carrier link which is adapted to be pivotally connected to the back-rest as defined above.

11. The linkage mechanism defined in claim 10 wherein said rear swing arm has a crank portion which is the portion which is connected to said carrier link as defined above, and wherein said front swing arm includes amain portion and an upper crank portion including a bite therebetween and wherein said carrier link is connected to said front swing arm at said bite, said crank portion of said front swing am being the portion thereof adapted to be connected to said seat as defined above.

12. The linkage mechanism defined in claim 11 wherein said actuator link is pivotally connected to a forward portion of said carrier link beyond the connection of the carrier link to said front swing arm.

13. The linkage mechanism defined in claim 8 further in-,

cluding a seat mounting plate pivotally connected to the upper end of said front swing arm and adapted to be fixed to the seat for mounting said front swing arm with respect thereto, a back-rest mounting plate pivotally connected to the rear portion of said carrier link and adapted to be fixed to said backrest for mounting said carrier link with respect thereto, said seat and back-rest mounting plates being pivotally interconnected.

14. The linkage mechanism defined in claim 10 further including a seat mounting plate pivotally connected to the upper end of said front swing arm and adapted to be fixed to the seat for mounting said front swing arm with respect thereto, a back-rest-mounting plate pivotally connected to the rear portion of said carrier link and adapted to be fixed to said backrest for mounting said carrier link with respect thereto, said seat and back-rest mounting plates being pivotally interconnected.

15. The sofa bed defined in claim 1 wherein said rear swing arm is connected to one of said carrier link and back-rest.

16; The sofa bed defined in claim 15 wherein said rear swing arm is connected to said carrier link and said front swing arm is connected to said seat.

17. For use in a sofa bed for supporting a seat and a backrest on an underlying base for movement between a sofa-bed position wherein the seatgenerally overlies the base with the back-rest in generally upright position and a bed position wherein the seat is projected forwardly from'the base and the back-rest is in a horizontal position generally coplanar with the seat; a linkage mechanism including a front swing arm adapted to be .pivotally connected to the base, a rear swing arm adapted to be pivotally connected to the base rearwardly of said front swing arm, and a carrier link pivotally connected to said front swing arm and adapted to be pivotally connected to said back-rest, said rear swing arm adapted to be connected to one of said back-rest and carrier link, and one of said carrier link and front swing arm adapted to be connected to said seat.

18. The linkage mechanism defined in claim 17 wherein said rear swing arm is connected to an intermediate portion of said carrier link, and said front swing arm is adapted'to be connected to said seat.

19. A linkage mechanism defined in claim 18 further including a seat mounting plate pivotally connected to said front swing arm and adapted to be fixed to the seat for mounting said front swing arm with respect to the seat, and a back-rest mounting plate pivotally connected to said carrier link and adapted to be fixed to the back-rest for mounting said carrier link with respect thereto, said seat and back-rest plates being pivotally interconnected for pivotally interconnecting said seat and back-rest.

20. The linkage mechanism defined in claim 19 further including a leg support for the seat adapted to be pivotally connected with respect to the seat for movement between retracted and extended positions relative to the seat, and-an actuator link pivotally connected to said carrier link and said leg support to actuate the leg support between said extended and retracted positions thereof.

21. The linkage mechanism defined in claim 17 wherein said front and rear swing arms are arranged to extend forwardly from the base when the seat and the back-rest are in the bed position and to extend rearwardly from the base when the seat and back-rest are in the sofa position, said front and rear swing arms being generally parallel to each other with a first portion of said carrier link extending in a direction transverse to said swing arms.

3,657,747 7 22. The linkage mechanism defined in claim 21 wherein said carrier link has a generally L-shape including a second portion extending at an angle to said first portion and being connected to said rear swing arm. 

1. A sofa bed including in combination, a base, a seat, a backrest, means pivotally interconnecting the back-rest and the seat permitting the back-rest to move between an upright position and a generally horizontal position generally coplanar with the seat, and linkage means supporting said back-rest and said seat on said base for movement between a sofa position wherein said seat closely overlies said base with said back-rest in upright position, and a bed position wherein said back-rest and said seat are in generally coplanar relationship with the back-rest overlying a substantial portion of said base and with the seat projected forwardly from the base, said linkage means including a front swing arm pivotally connected to the base, a rear swing arm pivotally connected to said base rearwardly of said front swing arm, and a carrier link pivotally connected to said back-rest and said front swing arm, one of said carrier link and said front swing arm being connected to said seat.
 2. A sofa bed or similar structure including in combination, a base, a seat, a back-rest, means pivotally interconnecting said back-rest to said seat for movement between an upright position and a horizontal position generally coplanar with the seat, linkage means for supporting said seat and back-rest between a sofa position wherein said seat overlies said base in close relationship therewith, said back-rest extending in generally upright position and a bed position wherein said seat is projected forwardly from the base with said back-rest in a horizontal position substantially coplanar with said seat, said linkage means including front and rear swing arms having lower end portions pivotally connected with respect to said base for swinging movement generally in a vertical plane, said front swing arm having an upper portion pivotally connected with respect to said seat, a carrier link having one end portion pivotally connected with respect to the back-rest and an intermediate portion pivotally connected with respect to said front swing arm, said rear swing arm being pivotally connected with respect to an intermediate portion of said carrier link.
 3. The structure defined in claim 2 further including a foldable support leg pivotally connected to said seat for movement between a retracted position under said seat and extended position projecting downwardly from said seat to support the same when in the bed position, means interconnecting said support leg and said linkage means for actuating said leg between the extended and retracted positions thereof in response to movement of said linkage means.
 4. The structure defined in claim 3 wherein said last defined means includes an actuator link pivotally connected to said carrier link.
 5. The structure defined In claim 4 further including a spring means for biasing the structure in said sofa and bed positions.
 6. The structure defined in claim 5 wherein said spring means includes a tension spring having one end anchored with respect to said base and having an opposite end connected to said seat.
 7. The structure defined in claim 4 wherein said carrier link has a generally L-shape including a main portion and a crank portion projecting from a rear end portion of the main portion, said rear swing arm being connected to said crank portion, said crank portion being the portion of said carrier link which is pivotally connected to said back-rest as defined above.
 8. For use in a sofa bed or similar structure for supporting a seat and a back-rest on an underlying base for movement between a sofa position wherein the seat generally overlies the base with the back-rest in generally upright position and a bed position wherein the seat is projected forwardly from the base and the back-rest is in horizontal position generally coplanar with the seat; a linkage mechanism including a front swing arm and a rear swing arm, the lower ends of said front and rear swing arms adapted to be pivotally connected with respect to the base, the upper end of said front swing arm adapted to be pivotally connected to said seat, a carrier link having a rear portion adapted to be pivotally connected with respect to the back-rest and having a forward portion pivotally connected with respect to an intermediate portion of said front swing arm, said rear swing arm having a portion pivotally connected with respect to a rear portion of said carrier link.
 9. The linkage mechanism defined in claim 8 further including a leg support for the seat adapted to be pivotally connected with respect to the seat for movement between retracted and extended position relative to the seat, and an actuator link having one end portion pivotally connected to said carrier link and an opposite end portion pivotally connected to said leg support to actuate the leg support between extended and retracted positions.
 10. The linkage mechanism defined in claim 9 wherein said carrier link has a generally L-shape including a main portion and a crank portion projecting from a rear end portion of the main portion, said rear swing arm being connected to said crank portion, said crank portion being the portion of said carrier link which is adapted to be pivotally connected to the back-rest as defined above.
 11. The linkage mechanism defined in claim 10 wherein said rear swing arm has a crank portion which is the portion which is connected to said carrier link as defined above, and wherein said front swing arm includes a main portion and an upper crank portion including a bite therebetween and wherein said carrier link is connected to said front swing arm at said bite, said crank portion of said front swing arm being the portion thereof adapted to be connected to said seat as defined above.
 12. The linkage mechanism defined in claim 11 wherein said actuator link is pivotally connected to a forward portion of said carrier link beyond the connection of the carrier link to said front swing arm.
 13. The linkage mechanism defined in claim 8 further including a seat mounting plate pivotally connected to the upper end of said front swing arm and adapted to be fixed to the seat for mounting said front swing arm with respect thereto, a back-rest mounting plate pivotally connected to the rear portion of said carrier link and adapted to be fixed to said back-rest for mounting said carrier link with respect thereto, said seat and back-rest mounting plates being pivotally interconnected.
 14. The linkage mechanism defined in claim 10 further including a seat mounting plate pivotally connected to the upper end of said front swing arm and adapted to be fixed to the seat for mounting said front swing arm with respect thereto, a back-rest mounting plate pivotally connected to the rear portion of said carrier link and adapted to be fixed to said baCk-rest for mounting said carrier link with respect thereto, said seat and back-rest mounting plates being pivotally interconnected.
 15. The sofa bed defined in claim 1 wherein said rear swing arm is connected to one of said carrier link and back-rest.
 16. The sofa bed defined in claim 15 wherein said rear swing arm is connected to said carrier link and said front swing arm is connected to said seat.
 17. For use in a sofa bed for supporting a seat and a back-rest on an underlying base for movement between a sofa-bed position wherein the seat generally overlies the base with the back-rest in generally upright position and a bed position wherein the seat is projected forwardly from the base and the back-rest is in a horizontal position generally coplanar with the seat; a linkage mechanism including a front swing arm adapted to be pivotally connected to the base, a rear swing arm adapted to be pivotally connected to the base rearwardly of said front swing arm, and a carrier link pivotally connected to said front swing arm and adapted to be pivotally connected to said back-rest, said rear swing arm adapted to be connected to one of said back-rest and carrier link, and one of said carrier link and front swing arm adapted to be connected to said seat.
 18. The linkage mechanism defined in claim 17 wherein said rear swing arm is connected to an intermediate portion of said carrier link, and said front swing arm is adapted to be connected to said seat.
 19. A linkage mechanism defined in claim 18 further including a seat mounting plate pivotally connected to said front swing arm and adapted to be fixed to the seat for mounting said front swing arm with respect to the seat, and a back-rest mounting plate pivotally connected to said carrier link and adapted to be fixed to the back-rest for mounting said carrier link with respect thereto, said seat and back-rest plates being pivotally interconnected for pivotally interconnecting said seat and back-rest.
 20. The linkage mechanism defined in claim 19 further including a leg support for the seat adapted to be pivotally connected with respect to the seat for movement between retracted and extended positions relative to the seat, and an actuator link pivotally connected to said carrier link and said leg support to actuate the leg support between said extended and retracted positions thereof.
 21. The linkage mechanism defined in claim 17 wherein said front and rear swing arms are arranged to extend forwardly from the base when the seat and the back-rest are in the bed position and to extend rearwardly from the base when the seat and back-rest are in the sofa position, said front and rear swing arms being generally parallel to each other with a first portion of said carrier link extending in a direction transverse to said swing arms.
 22. The linkage mechanism defined in claim 21 wherein said carrier link has a generally L-shape including a second portion extending at an angle to said first portion and being connected to said rear swing arm. 